I just have a quick question for you. Do you mod amps at all? If you do I might be interested in having you mod a JCM2000 DSL100 I just bought. And if not do you know of any sites that have reputable scematics for doing mods on these.

Just figured I ask since you grew up right down the road from me, and I'd rather give my buisness to you.

hey, I just found out about your amps, and wanted to tell you what an awesome job youve done designing and building them. I've always wanted to have some kind of job like this, even if it's just on the side. Keep up the good work and I'm looking forward to picking up a brigand someday.

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Thanks a lot for your help yesterday, but Fryette say they won't release schematics to anyone except authorized repair centers - they have offered to help me out though, so hopefully they'll be able to tell me what to do.

hey craig, how do you bolt on your chassis to the rear panel on your amps? i've thought of a few ways to secure it, but i'm wondering what would be the most secure and the most accessible way to do it. accessible, meaning not too hard to put it on. hopefully less likely for me to mess up on the drilling process. haha.

CECamps wrote on Jun 4th, 2010 at 6:03am :The 5751 should carry the same spec. The JAN will take that no problem. Not sure about the Sovtek, but honestly, I can't see it as being an issue with most tubes. That kind of voltage differential is par for the course when you're dealing with a CF.

CECamps wrote on Jun 4th, 2010 at 4:20am :Hey Shot, I got your PM but am on my phone and can't PM you back. So I'm going to answer you here.

Most 12AX7 datasheets specify that the heaters can be +100v/-200v with respect to the cathode voltage. In your case, from your calculations the heater is about -160v with respect to the cathode which is 40v within spec. So you're fine, no worries.

ohhhh ok. but it's a 5751 though. in particular, it's the JAN Phillips 5751 for the driving stage, cathode follower is a sovtek 5751...

craig,
Not trying to achieve anything...it just hasn't been done.
come on be an innovator. design the circuit in your free time.
ef86 tubes are getting better every day. some of the new ones are really good.

Hey, haven't gotten a chance to get inside the VTM, but is it possible in the VTM for one of the power tubes to have a different bias than the other?
I only have a resistor on one tube of mine, so I do not know if this is the case for my amp, but I had read this for another VTM user's experience at HCAF.
I do not know if he corrected the voltage divider when he added a bias pot, so maybe that's it, but I just wanted to ask you if I should add another 1 ohm resistor on the other tube so I can check if it's okay, or if this would be useless OCD worrying...haha.

you know, do you think it's wise to order the caps/resistors first, then get a blank board + turrets and have a real size caps/resistors to map out the layout on the board? i'm not so sure how much space i'll need between the components. and i'd want to keep that at a minimum, without causing any shorts. (i'm drawing my circuit board layout right now)

CECamps wrote on Apr 14th, 2010 at 9:04am :Tubes must be in and the amp of course must be connected to a speaker load. So you'd need to remove the chassis from the enclosure, locate the measurement points, and very carefully measure the voltages at those points with the amp powered on.

If you've never measured potentially lethal voltages before, I would recommend becoming intimately familiar with all necessary safety precautions. I can't stress that enough.

oh yeah, no worries. I've been modding this amp a bit, so I always drain caps first and have one in my pocket, etc...I'll let you know once I get some readings.